Sheet stretch bender with slide on main carriage



L. B. GREEN Oct. 26, 1954 SHEET STRETCH BENDER WITH SLIDE ON MAIN CARRIAGE 2 Sheets-Sheet 1 Filed NOV. 29, 1952 Mag? 5 m H A Oct. 26, L. B. GREEN SHEET STRETCH BENDER WITH SLIDE ON MAIN CARRIAGE Filed Nov. 29, 1952 2 Sheets-Sheet 2 INVENTOR. LEE 5. G/PEN BY I '0" I; I We f] I Patented Oct. 26, 1954 oFFicE sneer STRETCH BENDER wrrn- SLIDE.

on MAIN CARRIAGE Lee-B. Green, Lakewood, Ohio Application November 29, 1952, Serial No. 323,257

12 Claims. 1

This invention relates to stretch. bending machines of the. kind which operate to produce a combined stretching and bending operation ona metal sheet or other workpiece.

This application is a continuation-impart of original application Serial No. 305,377, filed August 20, 1952.

In that original application, there. is disclosed a stretch bending machine in which carriages having work gripping units thereon are movable along guideways provided on a pair of longitudinally aligned end frame members. Such and frame members extend in substantially opposite directions away from a die punch located therebetween and which punch is movable to engage and apply a bending force to an intermediate portion of a. workpiece extending thereacross while end portions of the workpiece are gripped by the gripping units.

The carriages are moved along the guideways of the frame by suitably driven lead screws and the movement thus imparted to the carriages serves to bring the gripping units into position to engage the ends of, the workpiece and also to produce the stretching force which is applied to the ends of the workpiece through the gripping units. Movement of the gripping units by such a lead screw actuation ofthe carriages hascertain limitations and disadvantages, one of. which is that the movement imparted to.the carriages by the lead screws is relatively slow.

It is, therefore, an object of this invention to provide an improved metal working machine of the above-mentioned stretch bending type having carriage means movable along guide means of a frame and in which work grippingmeans is carried by slide means operating, on guide means of the carriage means.

Another object is to provide a novel stretch bending machine, or the like, in which the car- 5 riage or carriages have transversely spaced guideways thereon and the slide means carrying the work gripping means includes block .members movable along such guideways.

Still another object is to provide a novel stretch bending machine in which the slide means is confined for substantially parallel movement on the carriage means by alignment control gearing on the meshed rack and pinion type connected between the slide meansand-the carriage means.

A. further object is to provide a new stretch bender of the character mentioned, in which the slide means includes a transverse sh'aftjournaled in the block members and having the rack engaging pinions fixed thereon;

Yet another object is toprovide anovel stretch bender of the kind above referred; to, in which the work gripping means 'isfcarried by a rocker means mounted on the transverse shaft between the block members.

It is alsoanobjectof this invention to, provide a novel, stretch, bender of the character above, indicated, inwhichfpower cylinder means mount.- ed on the carriage isconnectedowith the block members for imparting movement, to the slide means, and in which other power cylinder means mounted on the carriageis conhectedj with the rocker means for causing rocking of the latter.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements 'ofparts hereinafter described and'pa-rticularly setout in the claims hereof.

In the accompanying sheets of'drawings, form ing a part hereof:

Fig. 1 is a partial front elevation'ofastretch bending machine embodying this invention;

Fig. 2' is an end elevation, of "the machine showing the same withportions thereof broken away; and I Fig. 3 is a fragmentary elevational' view corresponding witha portion of Fig. 1; but -showing the same on a larger scale; I

As shown inthe drawings; the novel stretch bender ifl'compr'ises in general a mainframe H, a pair of pulling units l2 and I3 '*movable on the frame and adapted'to apply a stretching force-to opposite ends of a workpiece M; and a di'epunch I5 movable to engagean intermediate portion of the workpiece for applying a bending force thereto. 1

The frame I I comprisesan intermediate frame m'e'mber- I6 and a pair or substantially longitudinally aligned and frame members i1" and 18 which have their adiacentends connected with the intermediate framemmbr and extend in substantially opposite directions away from the die punch I5; The-die punch li'rhas-a convexly curved die surface l5 which includes rounded side portions I5 The die punch l5-1is suitably supported and guided in the intermediate member l6 and is adapted to be moved; into engagement with the workpiece M; in this case by a substantially vertical movement, by the operation of one or more power cylinder devices IS.

The and frame members W and i8-- and the pulling units 12" and i3 supported thereon, are substantially identical for opposite ends of the machine I0 and; hence-,; onlytheframe member I? andth'epullin'g unit- I2 need-be described in detail.

The pulling unit t2 comprises, in general, a'

'3 s3 carriage 2|) having a slide means 2| thereon, and a rocker means 22 rockably supported by such slide means and forming a support or carrier for a work gripping unit 23. The pulling unit |2 also comprises a grip head 24 forming a part of the gripping unit 23 and engageable with the workpiece |4 and through which head a stretching force is applied to the workpiece. Additionally, the pulling unit |2 comprises transversely spaced power cylinder devices 25, 26 mounted on the carriage and operable to impart movement to the slide means 2|, and a second pair of power cylinder devices 21, 28 also mounted on the carriage 20 and operable to impart rocking movement to the rocker means 22.

The end frame member ll is provided with longitudinally extending transversely spaced front and rear guide portions 28 and 39 forming a guideway 3| along which the carriage 26 of the pulling unit i2 is movable. The frame member IT is also provided with hold-down guide members 32 and 33 with which guide followers 34 and. 35, formed as depending brackets of the carriage 20, slidably cooperate. A suitable actuating means for the carriage 20 is also provided on the frame member H and is here shown as comprising a pair of lead screws 36 which cooperate with nuts 3! and are driven by an electric motor 38, or the like, through reduction gearings 39.

The carriage 20 is a suitably shaped rigid structure which includes upright side members 40 and 4|, and a transverse bottom wall 42 connecting such side members and having guide followers 43 and M thereon which are slidable on the guide members 29 and of the guideway 3|. The carriage 20 also comprises a pair of longitudinally extending guideway members or adapters 45 and 4B which are located inwardly of and against the side members and 4| and are bolted, or otherwise suitably secured, to the body of the carriage. The adapters and 46 have longitudinally extending guideway openings therein which provide the carriage 20 with a pair of transversely spaced longitudinal guideways 41. the main guideway 3| of the frame member l1 and extend in the same direction, that is to say, in a direction away from the die punch IS.

The slide means 2| comprises a pair of transversely spaced block members 39 which are slidably mounted in the guideways ll of the carriage 20, and a transversely extending shaft 5| extending between and mounted in the block members 29. The shaft 5| is mounted in the block members 49 by having reduced portions 52 journaled in bushings 53, which extend through the block members 59 transversely thereof. The slide means 2| is movable in the guideways 41 and relative to the die punch l5 by the power cylinder devices 25 and 26 of the carriage 20. These power cylinder devices have the cylinders thereof suitably mounted on the carriage 20 and have their piston rods 25 and 26 comiected with the block members 49 as by means of the threaded engagement 54.

The rocker means 22 comprises a pair of transversely spaced side members or brackets 55 and 55 and a connecting sleeve 51. The side members 55 and 56 are here shown as being in the form of substantially triangular metal plates which are welded, or otherwise rigidly secured, to the ends of the connecting sleeve 51. The triangular side members 55 and 56 are disposed with one apex or corner thereof directed downwardly, and such lower corners or apices are pro- The guideways 4'! are located above vided with mounting bearings which are here shown as being in the form of bushings 58 located in the outer ends of the sleeve 51. The shaft 5| extends through the connecting sleeve 51 and is provided with journal portions 58 on which the bearings 58 are mounted for rockably supporting the rocker means 22 on this shaft between the block members 49.

The side members 55 and 55 of the rocker means 22 are provided, at the upper corners thereof which are nearest the workpiece M, with bearings and 6| in which the gripping unit 23 is pivotally mounted, and at the other upper corners thereof which are more remote from the workpiece, these side members are provided with bearings 62. The gripping unit 23 is provided with projecting trunnions G4 and 65 which are journaled in the bearings 60 and GI and mount the gripping unit for swinging movement in the rocker means 22 between the spaced side members and 55 of the latter.

The rocker means 22 is rockable toward and away from the die punch l5 by the swinging movements of the rocker means about the axis of the transverse shaft 5| when such swinging movements are imparted to the rocker means by the cylinder devices 21 and 28. These cylinder devices are pivotally mounted on the carriage 20 by having pairs of trunnions 56 journaled in pairs of bearings 67 and 58 provided on the carriage. The cylinder devices 21 and 28 have their piston rods 69 connected with the side members 55 and 55 of the rocker means 22 by means of the yokes 63 and pivot pins T0 which extend through and are journalled in the bearings 62. The cylinder devices 25 and 26 for actuating the slide means 2| and the cylinder devices 27 and 28 for actuating the rocker means 22, are all double acting cylinder devices.

Further in accordance with the present invention, the slide means 2| is confined for substantially parallel translatory movement in the guideways 4'! so as to prevent skewing or misalignment of the slide means relative to the carriage 20 or misalignment of the gripping unit 23 relative to the workpiece or die punch. For this purpose, an alignment control means is provided which interconnects the slide means 2! with the carriage 20. This alignment control Ii means comprises meshing rack and pinion elements H and 12 of which the racks 1| are here shown as being secured to the side members 40 and 4| of the carriage 20 as by means of the screws 13.

The pinions 12 are fixed on the shaft 5|, as by being mounted on and keyed to reduced end portions 14 which project beyond the block members 49. The racks 1| are located adjacent the guideways 4'! of the carriage, such that during movement of the slide means 2| in these guideways by the power cylinder devices 25 and 26, the pinion 72 will roll along the racks. Since the pinions are connected with each other through the shaft 5|, the cooperation of the pinions with the racks will prevent skewing of the slide means 2| by confining the same to substantially parallel movements in the guideways 41 of the carriage 20.

By mounting the gripping units 23 on their associated slide means 2| instead of directly on the main carriages 20, the gripping units can be rapidly moved toward or away from the die punch l5 for engaging or releasing the grip heads 26 with the ends of the successive workpieces M when the latter are placed in the machine for 5.. the. performance. of the: desired stretch; bending. operations thereon. The relativelyslower.move-- ment'of the carriages" 20' canbetusedv aslan initial. adjustment of the machine for locating the'car riages relative to the; die punch 15 to suitrthe length of workpiece on which the machine isto operate and for subsequently adjustingthesetting of the machine whenother lengths of workpieces are to be accommodated therein.

When the gripping units23 aremounted on=the carriages 2-5 by providing the latter with the slide means 21, it is also possible to make use of' thepower cylinder devices 25 andaltfor. assisting the power cylinder devices zland 2.8-. in applying thestretching force to the workpiece. The movement of the slide means 2;! on thecar riage 28 as provided: by. the power-cylinder devices 25 and 26, can be accomplished" with very little wear on the relatively movable parts, thus minimizing the frequencyv with which the carriages are required to beimoved by the lead screws 3t and the resulting wear occurring on suchlead screws and the nuts Ell cooperating therewith. The present invention, therefore, provides a stretch bending machine having. greater operating speed, flexibility and'range of usefulness, as well as a machine which is capable of smoother and more accurate performance throughout a long period of. life.

The movements of the gripping units- 23 and their associated rocker means 22 during the stretchv bending operation performed on the workpiece M, are described in greater detail in the above-identified original application. For the purpose of the present disclosure, it is sufficient to explain that during the stretch bending operation the die punch I5 is moved" up wardly to impart a bending force to the intermediate portion of' the workpiece M. The stretching forces applied to the ends ofthe workpiece by the gripping units 23, cause the end portions of the workpiece to be drawn downwardly. and around the curved side portions [5 of the die'punch. During this stretching and bend ing of the end portions of the workpiece'around the curved side portions of the die punch, the rocker members 22 are swung relative to the die punch by the power cylinder devices 2.? and 28. and are also shifted. toward. or away from: the, die punch by movement impartedv to: the slide means 2i by the power cylinder devices 25" and 2E. The gripping units 23 swing in therocker' members 212 during the rocking andtranslatory movements of the latter, such that the resultantmovement of the gripping units causes them to. assume substantially upright positions adjacent thecurved side portions H5 of'the die-punch with the grip heads at pointing'in a generally upwarddirection.

From the foregoing description and the accompanying drawings, it will now be readily. under-- stood that this invention provides a novelstretch bending machine in which the work gripping units are carried by slide means provided on the main.

carriages and in which alignment control means interconnecting the slide means with. the' car riages, confines the slide means for a: desired& parallel translatory movement which: effectively prevents skewing or misalignment. It will, like-- wise, be understood that the slidemountingfor the gripping units provides for a more rapidand satisfactory movement of the gripping units for.

engaging the same with, or disengaging the samefrom, the successive workpiece.

. Although. the novel stretch bending: machine:

along-saidgtiidewasz, actuating mechanism operable. to movev said carriage along. said longitudinalguideway, meansdefining a pair of transversely spaced second guideways on said carriage, slide means comprising block members Y movablealong said .secondguidewaysanda-transe versely extending rotatable shaft. journaled in. saidblock members, actuating means-.roperable to move said slide means along said second guideways, a work gripping. device engageablewith-.a workpiece, and rocker means. carrying said. gripping device andsupportedby said shaft forrocking movement about-the.- axis of the latter.

2. In stretch bending apparatus, a frame-having, a .longitudinalguideway, a carriage movable alongsaid guideway, actuating mechanism operable to. move said carriage. along said longitudmal guideway, means defining a pair: of transversely spaced second guideways on said carriage, slide means. comprising block members:

movablealong saidlsecond guideways anda transversely extending rotatable-shaft journaled in said:

block members, actuating means operable to move said slide means along said second guideways, a work gripping deviceengageable with a workpiece, androcker means carrying said grippingv device and journaled for rocking movement on said shaft. between. said block: members.

3. Instretch bending apparatus, a frame-having a longitudinal guideway, a carriage movable along said-guideway, actuating mechanism oper able to'move said carriage along said longitudinal guideway, means defining a pair of transversely spaced second guideways on said carriage,

slide means comprising block members movable along saidsecond guideways and a. transversely extending rotatable shaft journaled in said block members, rocker means mounted on said shaft between said block members and rockableabout.

the axis of saidshaft, actuating means operable to move said slide. means along said second guideways, power cylinder means mounted on said. carriage and connected with said rocker means for imparting. rocking movement to the latter, a work gripping unit,v means pivotally mounting saidgrippinguniton said'rocker means for swinging movement relative to the latter, racks on said carriage adjacent .saidsecond guideways, and pin" ionsfixed on said. shaft andmeshing with said racks.

4. Stretch bending apparatus as defined in claim 3 in which said rocker means comprises a pair of. sidemembers spaced apart axially of said shaft, and, inwhich saidwork gripping unit is swingablein the space between said. side mem- ,bers.

and in which said cylinder deviceshave piston.

rods connected with said side members.

6. In: a stretch bending machine of the type having: a movable die. punch. engageable with an intermediate,- portion. of aworkpiece and-gripping.

devices engageable with the ends of the workpiece and located on opposite sides of said die punch, a main frame having a first guideway extending in a direction away from said die punch, a carriage movable along said first guideway and having laterally spaced upright longitudinal side members thereon provided with longitudinal slots defining a second guideway extending in a direction away from said die punch, slide means movable along said second guideway and forming a movable carrier for one of said gripping devices and including blocks slidable in said slots, actuating mechanism operable to move said carriage along said first guideway, actuating mechanism operable to move said slide means along said second guideway, a shaft extending transversely of said carriage and rotatably mounted in said blocks, and pairs of cooperating gear elements of the rack and pinion type spaced apart transversely of said carriage, the racks of the paired gear elements being attached to said side members adjacent said slots and the pinions being fixed on said shaft.

'7. In a stretch bending machine of the type having a movable die punch engageable with an intermediate portion of a workpiece and gripping devices engageable with the workpiece and located on opposite sides of said die punch, a main frame having a first guideway extending in a direction away from said die punch, a carriage movable along said first guideway and itself having a second guideway extending in a direction away from said die punch, slide means movable along said second guideway, actuating mechaiism operable to move said carriage along said first guideway, actuating mechanism operable to move said slide means along said second guideway, a transversely extending shaft rotatably mounted in said slide means, pairs of cooperating gear elements of the rack and pinion type spaced apart transversely of said carriage, the racks of the paired gear elements being attached to said carriage and the pinions being fixed on said shaft, and rocker means rockable on said shaft and having one of said gripping devices mounted thereon.

8. In a stretch bending machine, a movable die punch engageable with an intermediate portion of a workpiece extending thereacross, an elongated frame including substantially longitudinally aligned end frame members extending away from said die punch and located on opposite sides thereof, first guideways on said end frame members and extending longitudinally thereof, carriages movable along the guideways of said end frame members, actuating means perable to cause such movement of said carriages, second guideways on said carriages and extending in substantially the same direction as said first guideways, slide units movable along said second guideways, rocker units carried by said slide units and being rockable thereon toward and away from said die punch, gripping units swingably carried by said rocker units and adapted for gripping engagement with end portions of said workpiece, actuating devices operable to cause movement of said slide units along said second guideways, and alignment control gearing interconnecting said slide units with their respective carriages and confining said slide units to substantially parallel translatory movement along said second guideways.

9. In a stretch bending machine, a movable die punch engageable with an intermediate portion of a workpiece extending thereacross, an

elongated frame including substantially longitudinally aligned end frame members extending away from said die punch and located on opposite sides thereof, first guideways on said end frame members and extending longitudinally thereof, carriages movable along the guideways of said end frame members, actuating means operable to cause such movement of said carriages, laterally spaced upright longitudinal side members on said carriages and provided with longitudinal slots defining pairs of second guideways on said carriages and spaced apart transversely thereof, slide units on said carriages and each comprising a pair of block members slidable in a pair of said slots and a transversely extending shaft journaled in said pair of block members, gripping units carried by said slide units and adapted for gripping engagement with end portions of said workpiece, pairs of power cylinder devices on said carriages and connected with said block members and being operable to cause movement of said slide units along said second guideways, pairs of racks on said carriages adjacent the slots thereof, and pinions fixed on the shafts of said slide units and meshing with said pairs of racks.

10, In a stretch bending machine, a movable die punch engageable with an intermediate portion of a workpiece extending thereacross, an elongated frame including substantially longitudinally aligned and frame members extending away from said die punch and located on opposite sides thereof, first guideways on said end frame members and extending longitudinally thereof, carriages movable along the guideways of said end frame members, actuating means operable to cause such movement of said carriages, pairs of second guideways on said carriages and spaced apart transversely thereof, slide units on said carriages and each comprising a pair of block members slidable in a pair of said second guideways and a transversely extending shaft journaled in said pair of block members, rocker units swingably mounted on the shafts of said slide units between the pairs of said block members, gripping units carried by said rocker units and adapted for gripping engagement with end portions of said workpiece, transversely spaced power cylinder devices on said carriages and operably connected with said block members for causing movement of said slide units along said second guideways, pair of racks on said carriages adjacent the second guideways thereof, and pinions fixed on said shafts and meshing with said pairs of racks.

11. In a stretch bending machine, a movable die punch engageabie with an intermediate portion of a workpiece extending thereacross, an elongated frame including substantially longitudinally aligned end frame members extending away from said die punch and located on opposite sides thereof, first guideways on said end frame members and extending longitudinally thereof, carriages movabl along the guideways of said end frame members, actuating means operable to cause such movement of said carriages, pairs of second guideways on said carriages and spaced apart transversely thereof, slide units on said carriages and each comprising a pair of block members slidable in a pair of said second guideways and a transversely extending shaft journaled in said pair of block members, rocker units swingably mounted on the shafts of said slide units between the pairs of said block members, gripping units carried by said rocker units and adapted for gripping engagement with end portions of said workpiece, transversely spaced power cylinder devices of said carriages and operably connected with said block members for causing movement of said slide units along said second guideways, pairs of racks on said carriages adjacent the second guideways thereof, pinions fixed on said shafts and meshing with said pairs of racks, and power cylinder devices mounted on said carriages and operably connected with said rocker units for imparting swinging movement thereto.

12. A stretch bending machine as defined in claim 10 in which said rocker units comprise side members spaced apart axially of said shafts, and in which said gripping devices are pivotally mounted on the respective rocker units for swinging movement between the side members of the latter.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,825,721 Forward Oct. 6, 1931 1,885,855 Moran Nov. 1, 1932 2,217,172 Laussucq Oct. 8, 1940 2,218,503 Brooks Oct. 22, 1840 2,346,213 Flowers Apr. 11, 1944 2,431,173 I-Iawkes Nov. 18, 1947 2,446,089 Hochreiter July 27, 1948 2,527,412 Green Oct. 24, 1950 2,553,092 Hubbert May 15, 1951 

